Some of the most popular apps written for Google's Android phones do not tell users what is done with data they gather, says a study by US researchers. Half of 30 applications studied share location information and unique identifiers with advertisers. The team of computer scientists from Intel Labs, Penn State, and Duke University chose 30 out of the 358 most popular Android apps that, when installed, ask for permission to get at location, camera and audio data. Using an extension to the Android operating system called TaintDroid, created by the team, they logged what the applications did. As it appears blindly trusting others about their software isn't an good idea after all.